BillionToOne, Inc. officer and director David Tsao filed a Form 144 notice of proposed sale on November 2, 2026, covering 1,750 Class A shares with an aggregate market value of $198,310.00, to be sold on NASDAQ through Fidelity Brokerage Services LLC.

Key Highlights

  • Proposed sale: 1,750 Class A shares with an aggregate market value of $198,310.00, with an approximate sale date of November 2, 2026.
  • Filer relationship: David Tsao is listed as both an Officer and Director of BillionToOne, Inc. (NASDAQ:BLLN).
  • Original acquisition: The 1,750 shares were acquired on December 30, 2021, as Pre-IPO Shares from the Issuer, paid in cash on the same date.
  • Shares outstanding: 42,644,388 Class A shares were reported outstanding at the time of the notice.
  • Rule 10b5-1 plan: The filing indicates a plan adoption or instruction date of June 8, 2026.
  • Trust involvement: The filing notes that today's sale and recent sales occurred in the account of the Dt 2021 Irrevocable Trust by Icontrust LLC, trustee, with David Tsao identified as an account stakeholder in that trust.

Tsao's Proposed Sale and Prior Three-Month Transaction History at BillionToOne

According to the Form 144 filing, David Tsao, an officer and director of BillionToOne, Inc., headquartered at 1035 O'Brien Drive, Menlo Park, California, proposes to sell 1,750 Class A shares through Fidelity Brokerage Services LLC. The filing states the aggregate market value of the proposed sale is $198,310.00, and the approximate date of sale is November 2, 2026. The shares were originally acquired on December 30, 2021, as Pre-IPO Shares from the Issuer, with cash payment made on the same date.

The filing discloses several sales of Class A shares during the prior three months. Under the name David Tsao, sales include 10,000 shares on August 10, 2026, for gross proceeds of $928,600.00; 10,000 shares on August 25, 2026, for $1,000,000.00; 20,000 shares on September 9, 2026, for $1,975,400.00; 3,333 shares on September 24, 2026, for $416,625.00; and 20,000 shares on October 5, 2026, for $2,162,950.00. The Dt 2021 Irrevocable Trust is separately listed with sales of 3,500 shares on August 10, 2026, for $325,010.00; 1,750 shares on September 9, 2026, for $170,695.00; and 1,750 shares on October 5, 2026, for $184,012.50.

The filing's remarks section states: "Today's sale and sales within the past 3 months occurred in the account of the Dt 2021 Irrevocable Trust by Icontrust Llc, trustee on the account. David Tsao is an account stakeholder in the Dt 2021 Irrevocable Trust." The notice was signed by Daniel Tucci as a duly authorized representative of Fidelity Brokerage Services LLC, acting as attorney-in-fact for David Tsao.

What Was Disclosed

David Tsao, an officer and director of BillionToOne, Inc., filed a Form 144 on November 2, 2026, disclosing a proposed sale of 1,750 Class A shares valued at $198,310.00, with prior-three-month sales also disclosed for both Tsao and the Dt 2021 Irrevocable Trust, under a Rule 10b5-1 plan adopted June 8, 2026.